Okay, I don't want to pretend I'm an expert (and I didn't stay at a Holiday Inn Express last night), but I do have the hard-earned benefit of a bit of experience on this subject, and would like to post a word of caution to those of you who have yet to travel this road. Up to a few years ago my daily driver was a 1969 Road Runner convertible with factory air (bit of a rare combination). My 300F has factory air too, so this is also 300-related. Anyway, after a while the Road Runner's A/C got weak, and I determined it needed a recharge. Of course, being a 1969 vehicle it required R-12, which was silly expensive and hard to find. So after a little internet research and a few phone calls, I fell prey to the encouragements of those who said I could switch to modern R-134 (yes, you can!) with only a few modifications. These specified modifications included flushing the system, installing new, non-permeable hoses (apparently the R-134 molecules are smaller) and O-rings, a new receiver-drier, and R-134 compatible lubricant oil. I think all this ran me about $350 or so, and sure enough, while not as cold as before, the old Road Runner's A/C worked on R-134. Or at least it did for about six months, before the compressor packed up and died. After much more frustration and investigation, I learned a few things: while the mods I made allowed the R-134 to work, the basic DESIGN of my A/C system was unchanged. Included in that design were certain obscure components like the expansion valve and the EPR regulator that (of course) regulated the system BASED UPON TEMPERATURES AND PRESSURES UNIQUE TO R-12, and not R-134. Bottom line, as I came to understand it (see my first sentence) is that the R-134 confused the poor system, making it run practically all the time to maintain its cool. Eventually the overworked compressor seized up. Now, for those of you who live in Michigan or Illinois and use your A/C a month or two per year, it may be acceptable ( and may be the source of the wives' tale that "you can use R-134 in an R-12 system"), but for those of us in Southern California (or Texas or Florida) it just doesn't do it. Take my advice--- if you must have functioning A/C, either pony up and pay for genuine R-12, or contact Sanden and get a modern, non-original, non-concours R-134 system. Don't say you weren't warned. 300F'ly, Roger Karlson Carpinteria, CA [Non-text portions of this message have been removed] ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or go to http://autos.groups.yahoo.com/group/Chrysler300/join and select the "Leave Group" button For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/search.htm#querylangYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: Chrysler300-digest@xxxxxxxxxxxxxxx Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/